Journal Paper

2026

• Prebonding Baking of Wafers for Improved Surface Activated Bonding Kai Takeuchi, Junsha Wang, Akira Yamauchi, Tadatomo Suga, and Eiji Higurashi
  IEEE Transactions on Components, Packaging and Manufacturing Technology, vol. 16, pp. 602-608 (2026). DOI: 10.1109/TCPMT.2026.3662372

2025

• Au hollow pyramidal bumps for low-temperature low-pressure bonding fabricated via Au film transfer method Shintaro Goto, Kai Takeuchi, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, and Eiji Higurashi
  Sensors and Actuators A: Physical, Volume 395, p.116968 (2025). DOI: 10.1016/j.sna.2025.116968
• Low pressure Au–Au bonding using flat-topped micro-bump Au arrays fabricated by Au film transfer and coining methods Shintaro Goto, Kai Takeuchi, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, and Eiji Higurashi
  Japanese Journal of Applied Physics, vol. 64, p. 05SP08 (2025). DOI: 10.35848/1347-4065/adcc3a
• Wafer Bonding of GaAs and SiC via Thin Au Film at Room Temperature Kai Takeuchi and Eiji Higurashi
  Micromachines, vol. 16, p. 439 (2025). DOI: 10.3390/mi16040439
• Room temperature wafer bonding via polysilazane for vacuum sealing bonding Kai Takeuchi and Eiji Higurashi
  Japanese Journal of Applied Physics, vol. 64, p. 03SP36 (2025). DOI: 10.35848/1347-4065/adb4fb
• Room temperature bonding of Au plating through surface smoothing using polyimide template stripping Kai Takeuchi, Shogo Koseki, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, Takahiro Tsuda, Tomoaki Tokuhisa, Toshikazu Shimizu, and Eiji Higurashi
  Sensors and Actuators A: Physical, vol. 383, p. 116211 (2025). DOI: 10.1016/j.sna.2025.116211

2024

• Room temperature wafer bonding through conversion of polysilazane into SiO2 Kai Takeuchi, Tadatomo Suga, and Eiji Higurashi
  Scientific Reports, vol. 14, p. 1267 (2024). DOI: 10.1038/s41598-024-51800-6

2023

• Pixel-Wise 3-D Integration for High Performance Image Sensors (Co-authored work) Masahide Goto, Yuki Honda, Masakazu Nanba, Yoshinori Iguchi, Takuya Saraya, Masaharu Kobayashi, Eiji Higurashi, Hiroshi Toshiyoshi, Toshiro Hiramoto
  IEEE Transactions on Electron Devices, vol. 70, no. 9, 4705-4711 (2023). DOI: 10.1109/TED.2023.3298308
• Room temperature bonding of Au assisted by self-assembled monolayer Kai Takeuchi, Junsha Wang, Beomjoon Kim, Tadatomo Suga, and Eiji Higurashi
  Applied Physics Letters, vol. 122, no. 5, 051603 (2023). DOI: 10.1063/5.0128187

2022

• Room temperature bonding of GaN and diamond substrates via atomic layer Takashi Matsumae, Yuichi Kurashima, Hideki Takagi, Yusuke Shirayanagi, Shuichi Hiza, Kunihiko Nishimura, Eiji Higurashi
  Scripta Materialia, 215, 114725 (2022). DOI: 10.1016/j.scriptamat.2022.114725
• Hydrophilic direct bonding of GaN and Si substrates by wet treatments using H2SO4/H2O2 and NH3/H2O2 Shoya Fukumoto, Takashi Matsumae, Yuuichi Kurashima, Hideki Takagi, Masanori Hayase, Eiji Higurashi
  Japanese Journal of Applied Physics, vol. 61, no. SF, SF1005 (2022). DOI: 10.35848/1347-4065/ac5421
• Simple and low-temperature vacuum packaging process by using Au/Ta/Ti metal multilayer Shingo Kariya, Takashi Matsumae, Yuichi Kurashima, Hideki Takagi, Masanori Hayase, and Eiji Higurashi
  Japanese Journal of Applied Physics, vol. 61, no. 5, 051004 (2022). DOI: 10.35848/1347-4065/ac52b8
• Bonding formation and gas absorption using Au/Pt/Ti layers for vacuum packaging Shingo Kariya, Takashi Matsumae, Yuichi Kurashima, Hideki Takagi, Masanori Hayase, and Eiji Higurashi
  Microsystems & Nanoengineering, vol. 8, 2 (2022). DOI: 10.1038/s41378-021-00339-x
• Quantification of wafer bond strength under controlled atmospheres Kai Takeuchi and Tadatomo Suga
  Japanese Journal of Applied Physics, 61, SF1010 (2022).
• Low-temperature bonding of surface-activated polyimide to Cu Foil in Pt-catalyzed formic acid atmosphere Ying Meng, Yang Xu, Runhua Gao, et al.
  Journal of Materials Science: Materials in Electronics, 33, 2582–2589 (2022).
• Microfluidic chip connected to porous microneedle array for continuous ISF sampling Kai Takeuchi, Nobuyuki Takama, Kirti Sharma, Oliver Paul, Patrick Ruther, Tadatomo Suga, and Beomjoon Kim
  Drug Delivery and Translational Research, 12, 435–443 (2022).

2021

• Low-temperature direct bonding of SiC and Ga2O3 substrates under atmospheric conditions Takashi Matsumae, Yuichi Kurashima, Hideki Takagi, Hitoshi Umezawa, Eiji Higurashi
  Journal of Applied Physics, vol. 130, no. 8, 085303 (2021). DOI: 10.1063/5.0057960
• Low-temperature direct bonding of InP and diamond substrates under atmospheric conditions Takashi Matsumae, Ryo Takigawa, Yuichi Kurashima, Hideki Takagi, Eiji Higurashi
  Scientific Reports, vol. 11, 11109 (2021). DOI: 10.21203/rs.3.rs-266836/v1
• Application of thin Au/Ti double-layered films as both bonding layer and getter for MEMS Yuichi Kurashima, Takashi Matsumae, Eiji Higurashi, et al.
  Microelectronic Engineering, vol. 238, 111513 (2021). DOI: 10.1016/j.mee.2021.111513
• High thermal performance GaN-on-graphite composite bonded substrate for nitride electronics Lei Li, Tomohiro Obata, Aozora Fukui, Kai Takeuchi, Tadatomo Suga, Atsushi Tanaka, Akio Wakejima
  Applied Physics Express, 14, 091002 (2021).
• Sequential Plasma Activation for Low Temperature Bonding of Aluminosilicate Glass Kai Takeuchi, Fengwen Mu, Akira Yamauchi, and Tadatomo Suga
  ECS Journal of Solid State Science and Technology, 10, 054007 (2021).
• Room Temperature Wafer Bonding of Glass Using Aluminum Oxide Intermediate Layer K. Takeuchi, F. Mu, Y. Matsumoto, and T. Suga
  Advanced Materials Interfaces, 2001741 (2021).

2020

• Heterogeneous direct bonding of diamond and semiconductor substrates using NH3/H2O2Shoya Fukumoto, et al.
  Applied Physics Letters, vol. 117, no. 20, 201601 (2020).
• Low-temperature direct bonding of diamond (100) substrate on Si waferTakashi Matsumae, et al.
  Scripta Materialia, vol. 191, pp. 52-55 (2021).
• Heterogeneous GaN-Si integration via plasma activation direct bondingTakashi Matsumae, et al.
  Journal of Alloys and Compounds, vol. 852, 156933 (2021).
• Room-Temperature Bonding of Aluminum Nitride Ceramics and Semiconductor SubstratesTakashi Matsumae, et al.
  Ceramics International, vol. 46, no. 16, pp. 25956-25963 (2020).
• Fabrication of Multi-Stacked Integrated Circuit for High Performance Image SensorsNaoki Nakatani, et al.
  Transactions of JIEP, vol. 13, E20-004 (2020).
• Effect of Au Film Thickness and Surface Roughness on Room-Temperature SABMichitaka Yamamoto, et al.
  Micromachines, vol. 11, no. 5, 454 (2020).
• Demonstration of GaN/LiNbO3 Hybrid Wafer Using Room-Temperature SABRyo Takigawa, et al.
  ECS Journal of Solid State Science and Technology, vol. 9, no. 4, 045005 (2020).
• Room-temperature pressureless wafer scale hermetic sealing using SAB with ultrathin Au filmsMichitaka Yamamoto, et al.
  Japanese Journal of Applied Physics, vol. 59, no. SB, SBBB01 (2020).
• A Novel Strategy for GaN-on-Diamond Device with a High Thermal Boundary ConductanceFengwen Mu, et al.
  Journal of Alloys and Compounds, 905, 164076 (2020).
• Flexible and Porous Microneedles of PDMS for Continuous Glucose MonitoringKai Takeuchi, et al.
  Biomedical Microdevices, 22, 79 (2020).

2019

• Ultrathin adhesive layer between LiNbO3 and SiO2 for bonded LNOI waveguideRyo Takigawa, Eiji Higurashi, and Tanemasa Asano
  Japanese Journal of Applied Physics, vol. 58, no. SJ, SJJE06 (2019).DOI
• Triple-Stacked Au/SiO2 Hybrid Bonding With 6-μm-Pitch Au Electrodes on SOIYuki Honda, et al.
  IEEE TCPMT, vol. 9, no. 9, pp. 1904-1911 (2019).DOI
• 極薄Au薄膜を用いたウェハスケール・大気中常温接合のためのプラズマ処理方法山本道貴, 松前貴司, 他
  電気学会論文誌Ｅ, vol. 139, no. 7, pp. 217-218 (2019).
• Surface activated bonding of Au/Cr, Au/Ta and Au/Pt/Ti films after degas annealingTakashi Matsumae, et al.
  Microelectronic Engineering, vol. 214, pp. 68-73 (2019).DOI
• Direct Bonding of an Electroformed Cu Substrate and Si Chip at Room TemperatureT. Matsumae, et al.
  ECS Journal of Solid State Science and Technology, vol. 8, no. 4, pp. 253-257 (2019).
• Optical evaluation of nanocomposite metamaterials fabricated by nano-printing techniqueRyohei Hokari, et al.
  Microelectronic Engineering, vol. 211, pp. 44-49 (2019).DOI
• Growth Behavior of Au Films on SiO2 Film and Direct Transfer for Smoothing Au SurfacesMichitaka Yamamoto, et al.
  IJAT, vol. 13 no. 2, pp. 254-260 (2019).
• Residual stress in Lithium Niobate film layer of LNOI/Si hybrid waferRyo Takigawa, et al.
  Micromachines, vol. 10, no. 2, 136 (2019).DOI
• Comparison of argon and oxygen plasma treatments for ambient room-temperature Au-Au bondingMichitaka Yamamoto, et al.
  Micromachines, vol. 10, no. 2, 119 (2019).DOI
• 水素ラジカル処理した銅表面のX線光電子分光法(XPS)による酸化挙動解析申盛斌, 日暮栄治, 他
  電気学会論文誌Ｅ, vol. 139, no. 2, pp. 38-39 (2019).
• Quarter Video Graphics Array Digital Pixel Image Sensing using Pixel-Wise 3-D IntegrationMasahide Goto, et al.
  IEEE Transactions on Electron Devices, vol. 66, no. 2, pp. 969-975 (2019).DOI
• De-bondable SiC-SiC wafer bonding via an intermediate Ni nano-filmFengwen Mu, et al.
  Applied Surface Science, vol. 465, no. 28, pp. 591-595 (2019).DOI
• Microfluidic chip to interface porous microneedles for ISF collectionKai Takeuchi, et al.
  Biomedical Microdevices, 21, 28-37 (2019).

2018

• Hematocrit-insensitive Absolute Blood Flow Rate Measurement by MEMS-based LDVNobutomo Morita, et al.
  Sensors and Materials, vol. 30, no. 12, pp. 3009-3020 (2018).DOI
• Room-temperature wafer bonding of LiNbO3 and SiO2 using modified SABRyo Takigawa, et al.
  JJAP, vol. 57, no. 6S1, 06HJ12 (2018).DOI
• High-Speed InP/InGaAsSb DHBT on High-Thermal-Conductivity SiC SubstrateYuta Shiratori, et al.
  IEEE Electron Device Letters, vol. 39, no. 6, pp. 807-810 (2018).DOI
• Properties of various plasma surface treatments for low-temperature Au-Au bondingMichitaka Yamamoto, et al.
  JJAP, vol. 57, no. 4S, 04FC12 (2018).DOI
• Heterogeneous integration based on low-temperature bonding for advanced optoelectronic devicesEiji Higurashi
  JJAP, vol. 57, no. 4S, 04FA02 (2018).DOI
• Grasping force control for a robotic hand by slip detection using micro LDVNobutomo Morita, et al.
  Sensors, vol. 18, no. 2, 326 (2018).DOI
• Evaluation of hydrogen radical treatment for indium surface oxide removalKohta Furuyama, et al.
  JJAP, vol. 57, no. 2S1, 02BC01 (2018).DOI
• Functionalized microneedles for continuous glucose monitoringKai Takeuchi and Beonjoon Kim
  Nano Convergence, 5, 28-37 (2018).
• Room temperature bonding and debonding of polyimide film and glass substrateKai Takeuchi, et al.
  JJAP, 57, 02BB05 (2018).
• Mechanism of bonding and debonding using SAB method with Si intermediate layerKai Takeuchi, et al.
  JJAP, 57, 04FC11 (2018).